iiddttuunnee -- Command

Set a tunable system value
/eettcc/ccoonnff/bbiinn/iiddttuunnee [-ffmm] _s_w_i_t_c_h _v_a_l_u_e

The command iiddttuunnee lets you ``tune'' a variable in the COHERENT kernel.  It
also performs  some sanity checking, to  help ensure that you  do not set a
value to  an impossible value.  It and the  related command ccoohhttuunnee largely
replace the need for the command ppaattcchh.

To use iiddttuunnee, simply invoke it  along with the variable you wish to modify
and the  value to  which you wish  to set it.   For example, to  change the
maximum size of a shared-memory segment to 128,000 bytes, type the command:

    /etc/conf/bin/idtune SHMMAX 128000

For  the  new  setting to  come  into  effect,  you  must use  the  command
/eettcc/ccoonnff/bbiinn/iiddmmkkccoohh to build a new  kernel, and then boot the newly built
kernel.

iiddeennaabbllee recognizes the following two command-line options:

-ff   iiddttuunnee by default will ask you if you are sure that you want to make a
     given change.  This option suppresses that behavior.

-mm   Check that  the value of  _s_w_i_t_c_h is no  less than _v_a_l_u_e.  If the value
     _s_w_i_t_c_h is less than _v_a_l_u_e,  then iiddttuunnee raises it to _v_a_l_u_e; otherwise,
     it leaves the value of _s_w_i_t_c_h alone.

iiddttuunnee works by modifying  the file /eettcc/ccoonnff/ssttuunnee, which holds the values
of system  variables that  users can  set.  ssttuunnee consists  of a  series of
entries like the following:

     LOOP_COUNT     16
     DUMP_USERS     2
     MONO_COUNT     0
     VGA_COUNT      4

The  allowed  range  of  values  for  a  given  variable  is  set  in  file
/eettcc/ccoonnff/mmttuunnee, which consists of a series like the following:

    STREAMS_HEAP    8192    32768   131072
    MONO_COUNT      0       4       8
    VGA_COUNT       0       4       8
    NBUF_SPEC       0       0       5000
    NHASH_SPEC      0       1021    5000
    NINODE_SPEC     0       128     1024
    NCLIST_SPEC     0       64      1024

The first column gives the variable, the second gives its minimum allowable
value, the third gives its default value, and the last its maximum value.

You can read mmttuunnee and ssttuunnee  to see what kernel variables you can set, and
to find the range of values allowed for each.  Note, however, that you must
_n_e_v_e_r modify ssttuunnee or mmttuunnee by  hand.  If you do so, you may build a kernel
that is unbootable or that trashes your file system.

_S_e_e _A_l_s_o
ccoohhttuunnee, ccoommmmaannddss, iiddeennaabbllee, iiddmmkkccoohh
